Antimicrobial Susceptibility Testing (AST) is a laboratory procedure used to determine the effectiveness of antibiotics, antifungals, antivirals, or antiparasitic agents against specific microorganisms. By exposing pathogens to different antimicrobial agents, AST helps identify which drugs are most effective in treating infections. This information guides clinicians in selecting the most appropriate therapy, promotes targeted treatment, and plays a vital role in combating antimicrobial resistance (AMR).